1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) and method for driving the same, in particular improving a response characteristic of a liquid crystal employing a charge-sharing driving mode.
2. Description of the Prior Art
In general, LCDs, as devices for displaying an image by adjusting light transmittance through a change in alignment of liquid crystal molecules under the action of an electric field, have been developed from a TN-LCD (Twisted Nematic LCD) to an STN-LCD (Super Twisted Nematic LCD), a MIM-LCD (Metal Insulator Metal LCD) and a TFT-LCD (Thin Film Transistor LCD) in that order, and simultaneously their display performance has been remarkably improved. Such LCDs have drawn attention as a device capable of substituting for CRTs (Cathode Ray Tubes) due to an advantage in that it is possible to make lighter and simpler, and has a tendency toward gradual increase in demand as it has widely applied to notebook computers or mobile communication apparatuses.
However, as for LCDs, due to specific characteristics of the liquid crystal molecule, a time delay is accompanied to control the alignment of the liquid crystal molecules, and at the same time response speed of the liquid crystal molecule is slower than a conversion speed of a frame. This acts as a main cause making an image outline blurry or deteriorating a quality of image when establishing moving pictures.
One technique, which has been generally used to solve these problems, is to accelerate the response speed of the liquid crystal molecule. To this end, a level of previous input data is compared with that of present input data, and then an LCD panel is subject to over-driving at the maximum and minimum output voltages of a source driver integrated circuit. Such a technique is disclosed in Korean unexamined patent application publication No. 2003-4049, filed on Jun. 25, 2002.
The conventional LCD as mentioned above incurs over-shoot and under-shoot of an output voltage, due to excessive adjustment of the output voltage of a liquid crystal driving unit, that is, the source driver IC, and thus excessive stress is applied to an output buffer of the source driver IC.
Additionally, during over-driving, a DC/DC converter applying a supply voltage to the source driver IC is subject to strong load fluctuation, thereby deteriorating stability and load adjustment capability. This output instability of the DC/DC converter has an influence on its peripheral element such as a timing controller, thereby causing interference to high-frequency clocks and data.
Therefore, the conventional LCD has problems in that consumption of electric power is increased as a whole due to over-driving, and that the liquid crystals themselves are deteriorated due to applied stress.